How cast Enum to String in Stream API?

public class User {
    private String name;
    private Role role;
 }

enum Role {
    ADMIN, MODERATOR, USER
}

List<User> users = Arrays.asList(
                new User("Alex", Role.USER),
                new User("Tom", Role.ADMIN),
                new User("Bob", Role.MODERATOR),
                new User("Mila", Role.USER),
                new User("Kate", Role.MODERATOR)
        );

Map<Role, Long> count = users.stream()
                .collect(Collectors.groupingBy(User::getRole, Collectors.counting()));

Result : {ADMIN=1, USER=2, MODERATOR=2}

I want to group by role and calculate the number of users, using stream API. When I used Map<Role, Long> all is ok.

But I need Map<String, Long> and have a compile error. I don't get how to cast Enum to String in this case?

Use user.getRole().name() instead of only user.getRole().

name() method will return the name of your defined Enum (eg. ADMIN) in String format.